Energy Transformations and Conservation Energy Transformations What does

Energy Transformations and Conservation

Energy Transformations • What does flowing water have to do with electricity? • You may already know that the mechanical energy of moving water can be transformed into electrical energy.

Most forms of energy can be transformed into other forms • A change from one form of energy to another is called an energy transformation. • Some energy changes involve single transformations, while others involve many transformations.

Single Transformations • Sometimes, one form of energy needs to be transformed into another to get work done. • For example, a toaster transforms electrical energy to thermal energy to toast your bread. • A cell phone transforms electrical energy to electromagnetic energy that travels to other phones.

• Your body transforms the chemical energy in your food to mechanical energy you need to move your muscles. • Chemical energy in food is also transformed to thermal energy your body uses to maintain its temperature.

Multiple Transformations • Often, a series of energy transformations is needed to do work. • For example, the mechanical energy used to strike a match is transformed first to thermal energy. • The thermal energy causes the particles in the match to release stored chemical energy, which is transformed to thermal energy and the electromagnetic energy you see as light.

• In a car engine, another series of energy conversions occurs. • Electrical energy produces a spark. • The thermal energy of the spark releases chemical energy in the fuel. • The fuel’s chemical energy in turn becomes thermal energy. • Thermal energy is converted to mechanical energy used to move the car, and to electrical energy to produce more sparks.

Transformations Between Potential and Kinetic Energy • One of the most common energy transformations is the transformation between potential energy and kinetic energy. • In waterfalls such as Niagara Falls, potential energy is transformed to kinetic energy. • The water at the top of the falls has gravitational potential energy. • As the water plunges, its velocity increases. • Its potential energy becomes kinetic energy.

Energy Transformation in Juggling • Any object that rises or falls experiences a change in its kinetic and gravitational potential energy. • Look at the orange in the picture on the right. • When it moves, the orange has kinetic energy. • As it rises, it slows down. • Its potential energy increases as its kinetic energy decreases.

• At the highest point in its path, it stops moving. • Since there is no motion, the orange no longer has kinetic energy. • But it does have potential energy. • As the orange falls, the energy transformation is reversed. • Kinetic energy increases while potential energy decreases.